Airspeed

n. speed of an aircraft relative to the air through which it moves

Airspeed is the speed of an aircraft relative to the air. There are several different measures of airspeed: indicated airspeed, calibrated airspeed, equivalent airspeed and true airspeed.It is measured within the flying aircraft with an airspeed indicator - a device which connects to ram air pressure from outside the aircraft and compares it to non-moving air pressure outside the aircraft. The ram pressure is sampled by a device called a pitot tube, carefully located clear of the propeller blast and other airflow distortions. There is also typically one or more static ports carefully located on the outside of the aircraft.
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Noun
1. the speed of an aircraft relative to the air in which it is flying
(hypernym) speed, velocity

The speed of an aircraft relative to its surrounding air mass. The unqualified term "airspeed", means one of the following. 1) Indicated Airspeed. The speed shown on the aircraft airspeed indicator. This is the speed used in pilot/controller communications under the general term "airspeed." 2) True Airspeed. The airspeed of an aircraft relative to undisturbed air. Used primarily in flight planning and en route portion of flight. When used in pilot/controller communications, it is referred to as "true airspeed" and not shortened to "airspeed." (FAA4)

The speed of an aircraft relative to its surrounding air mass. The unqualified term "airspeed" means one of the following:

a. Indicated Airspeed
The speed shown on the aircraft airspeed indicator. This is the speed used in pilot/controller communications under the general term "airspeed."
(Refer to 14 CFR Part 1.)

b. True Airspeed
The airspeed of an aircraft relative to undisturbed air. Used primarily in flight planning and en route portion of flight. When used in pilot/controller communications, it is referred to as "true airspeed" and not shortened to "airspeed."